I'm an automation and controls engineer, which means I spend a lot of time writing code that automates factory processes.

I'm an automation and controls engineer, which means I spend a lot of time writing code that automates factory processes. But I'm writing code on specialized computers called programmable logic controllers like this one. And automation engineers typically use the five specialized PLC programming languages known as the IEC 61131-3 programming languages. First off is ladder diagram, sometimes called ladder logic. This is a very visual based programming language that sort of stems from the origins of automation and controls, which was physical relays doing automated things in factories. So when you look at ladder logic, ladder diagram, you're looking at top to bottom visual blocks of if and or and and statements. And ladder diagram is likely the most commonly used and seen automation programming language. But closely following it is probably structured text. Structured text is the closest to what you might consider a conventional programming language. Many complicated functions are easiest to do or only feasible to do in structured text. Those with conventional software computer science or programming backgrounds are likely going to find structured text is the closest to what they've seen before and are comfortable with. Also incredibly common is FBD or function block diagram. These are sort of like ladder logic in the sense that they're visual blocks of code, but they're sort of free floating in space and you tie input commands to a block that does a function and then you can tie output statuses and parameters and variables to the output of those function blocks. Next is SFC or sequential function chart and this technically isn't a programming language but a visual way of stepping through functions and representing a larger program in a sequential fashion that says do this function, wait for this transition condition and then do this function. The higher level language that organizes subfunctions and submodules that get written in some other language. And the fifth language is instruction list and it's a little bit of a weird one. It's actually been deprecated for future use, so going forward new systems will not be getting commissioned with instruction list. Difficult to interpret and not particularly intuitive to write, read or troubleshoot. The need for that language is going away. And so it's also sort of fair to say in modern times the fifth programming language is really like a C++. As more and more PLCs are running more and more advanced processors and capable of more of the functionality that a conventional computer has been capable of. Many platforms are also supporting C++. So those are the PLC programming languages. Be sure to follow the Master Tech if you want to learn more about automation and controls.